Vaillant ecoTEC VU 466/4 - Replacing the heat exchanger

Installation and maintenance instructions ecoTEC 0020029172_0350
1
2
3
4
Fig. 10.2 Dismantling the fan with gas valve
• Pull the plug (4) out of the gas valve.
• Pull the plugs (2) out of the fan.
• Unfasten the four screws (3) on the compact thermal
module (1).
• Remove the complete unit "gas valve/fan".
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6
Fig. 10.3 Screwed connection gas valve/fan
• Release both fixing screws (5) on the gas valve and
remove the fan from the gas valve.
• Replace the defective component.
a
Caution!
The gas valve and fan must be returned to their
previous installation position. Use a new seal!
• Screw the fan to the gas valve. Use new seals.
• Re-install the complete "gas valve/fan" boiler in the
reverse sequence.
• After completing the work, perform a gas-tightness
check and function check (see Chapter 8.10)
10.4 Replacing the heat exchanger
d
Danger!
Before replacing the component, observe the
safety information in Chapter 10.1.
• Disconnect the boiler from the power mains as
described in Chapter 10.1, and close the gas isolation
valve.
• Close the service valves in the heating flow and return
and drain the boiler.
• Dismount the compact thermal module as described
under 8.3.1.
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4
5
2
3
Fig. 10.4 Replacing the heat exchanger
• Pull out the clip (4) of the condensate siphon (5).
• Unfasten the screw connections on the condensate
siphon and pull it off the heat exchanger.
• Disconnect the flow connection (2) and the return
connection (1) on the heat exchanger.
• Slacken the white plastic nut between the siphon and
heat exchanger.
• Unfasten the three screws (3) on the heat exchanger
and take it out of the boiler.
• Unfasten both brass connection pieces (positions 1
and 2) on the old heat exchanger and screw these
onto the new one. Use new seals in the process!
• Mount the new heat exchanger in reverse order and
replace the seals.
• Fill and bleed the boiler, also, if necessary, the system
after installing the new heat exchanger.
• After completing the work, check for gas and water
leaks and perform a function check (see Chapter 6.4).
10 Replacing components